Sub flow based queueing management

ABSTRACT

Nodes and related methods are directed to grouping PDUs into sub flows based on information elements of the PDUs and selecting PDUs from sub flow according to a priority indicator calculated for each sub flow. The selected PDUs are sent in an order that provides a fairer resource sharing for real time like service sessions at the expense of bandwidth greedy applications. Reduced delay variability and/or reduced PDU loss probability may be obtained for real time like services when network transport resources are shared with bandwidth greedy services, such as file transfers over TCP.

TECHNICAL FIELD

This disclosure pertains in general to the field of queue management,and more particularly to a method and a node for sub flow based queuingmanagement of Protocol Data Units (PDUs).

BACKGROUND

Data queuing and management techniques therefore are well known and areused in existing and commercially available network equipments. Thesetechniques are mainly developed for link characteristics in networkswith stable and static bandwidth conditions.

Due to various reasons the bandwidth capacity in a network can vary overtime.

The need for traffic queuing for data services using a communicationsystem varies with the available capacity. The desired data queuelengths in good conditions differ from the ones in poor conditions.

There is hence a more challenging demand on data queuing management insystems with varying conditions than compared to systems with static andstable conditions, for reliable data services.

Utilizing known and existing techniques for data queuing incommunication systems with varying conditions may reduce the quality ofexperience for delay sensitive services due to the fact that arelatively long queuing delay is allowed in such communications systems.

SUMMARY

In view of the above, it is a general object of embodiments of theinvention to provide for improved data queuing management. Also, itwould be advantageous to provide data queuing management with which thedelay and/or delay variance for real time services can be lowered.

According to one aspect of this disclosure a method for queue managementof PDUs is disclosed. The method comprises receiving a flow of PDUs andassociating each PDU with a flow reference that is determined based oninformation elements in at least each PDU header. The method alsocomprises grouping all PDUs having the same flow reference intorespective sub flows, and determining a priority indicator for each subflow based on the length of the sub flows. In addition, the methodcomprises selecting one or more PDUs from sub flows in an order of thesub flows which is indicated by the priority indicator, and sending theselected PDUs.

Determining of the priority indicator for each sub flow may be based onthe length of the received PDUs in each sub flow.

The determining of the priority indicator for each sub flow based on thelength of the sub flows may comprise determining the highest priorityfor each sub flow having only one single PDU.

The associating each PDU with a flow reference may comprise associatingeach PDU of the same service session with the same flow reference, whereeach PDU is part of a service session as indicated by each PDU header.

The method for queue management of PDUs may further comprise detecting atriggering condition comprising detecting one of: receipt of MediumAccess Control-d (MAC-d)-layer information, receipt of informationrelated to the control layer of Radio Link Control (RLC), and receipt ofa PDU into a sub flow, wherein the detecting of the triggering conditiontriggers the determining of the priority indicator, the selecting one ormore PDUs from sub flows, or the sending the selected PDUs.

The information elements, in associating each PDU with a flow referencethat is determined based on information elements in at least each PDUheader, may comprise at least one of: a protocol or application type, asource Internet Protocol (IP) address, a destination IP address, asource port and a destination port, which all are at least associatedwith a service session.

Receiving a flow of PDUs may comprise receiving a flow of PDUs within asingle Radio Access Bearer (RAB).

The receiving of a flow of PDUs may comprise receiving PDUs on a firstprotocol layer, wherein the sending the selected PDUs may comprisesending the selected PDUs on a second protocol layer, and wherein thefirst protocol layer is a higher protocol layer than the second protocollayer.

The first protocol layer in receiving PDUs on a first protocol layer,may comprise any of Internet Protocol (IP), Transmission ControlProtocol (TCP), User Datagram Protocol (UDP), Real-Time Control Protocol(RTCP), Datagram Congestion Control Protocol (DCCP), Stream ControlTransmission Protocol (SCTP), Resource reservation Protocol (RSVP),Real-Time Transport Protocol (RTP), and Explicit Congestion Notification(ECN).

The second protocol layer within the method for queue management of PDUsmay comprise RLC layer or MAC-d, layer.

According to a second aspect of the present disclosure, a node for queuemanagement of PDUs is disclosed. The node comprises a first interfacethat is configured to receive a flow of PDUs and associate each PDU witha flow reference that is determined based on information elements in atleast each PDU header, and a classifier that is configured to group allPDUs having the same flow reference into respective sub flows. The nodealso comprises a selector that is configured to determine a priorityindicator for each sub flow based on the length of the sub flows, andselect one or more PDUs from sub flows in an order of the sub flowswhich is indicated by the priority indicator. In addition, the nodecomprises a second interface configured to send the selected PDUs.

The selector of the node may be configured to determine the priorityindicator for each sub flow based on the PDUs grouped into each subflow.

The selector of the node may be configured to determine the highestpriority for each sub flow having only one single PDU.

The first interface of the node may be configured to associate each PDUof the same service session with the same flow reference, where each PDUis part of a service session as indicated by the PDU header.

The selector of the node may be configured to detect a triggeringcondition that comprises one of: receipt of MAC-layer information,receipt of information related to the control layer of Radio LinkControl, RLC, and receipt of a PDU grouped into a sub flow, wherein thedetection of the triggering condition triggers the selector to determinethe priority indicator, or to select one or more PDUs from sub flows, orthe second interface to send the selected PDUs.

The first interface of the node may be configured to receive PDUs on afirst protocol layer, and wherein the second interface may be configuredto send the selected PDUs on a second protocol layer, wherein the firstprotocol layer is a higher protocol layer than the second protocollayer.

The first interface of the node is configured to receive PDUs on a firstprotocol layer where the first protocol layer may comprise any of: IP,TCP, UDP, RTCP, DCCP, SCTP, RSVP, RTP and ECN.

The second interface of the node is configured to send PDUs on a secondprotocol layer where the second protocol layer may comprise RLC layer orMAC-d, layer.

The node for queue management of PDUs may be a Radio Network Controller,RNC, a Base Station, a NodeB or an eNodeB.

Embodiments of the present disclosure come with one or more thefollowing advantages:

The present disclosure has substantial effect in systems where theavailable link capacity varies over time. Especially high effect isgained in systems with transmission links that experience a large delayvariance, for instance mobile communication systems such as UniversalMobile Telecommunications System (UMTS), World Interoperability forMicrowave Access (WiMAX), or Long Term Evolution (LTE).

One advantage with some embodiments of the present disclosure is that itresults in reduced delay variability for real time like services whennetwork transport resources are shared with bandwidth greedy services,such as file transfers over TCP.

Another advantage with some embodiments of the present disclosure is areduced PDU loss probability for real time-like services when networktransport resources are shared with bandwidth greedy services, such asfile transfers over TCP.

Real time services are, in the end to end perspective, sensitive to longdelays, PDU losses, jitter, and insufficient bandwidth. Some embodimentsof the present disclosure increase the chance for real time services toget desired bandwidth capacity and reduces both the delay variance andthe risk for PDU losses.

BRIEF DESCRIPTION OF DRAWINGS

These and other aspects, features and advantages of which thisdisclosure is capable of, will be apparent and elucidated from thefollowing description of embodiments of this disclosure, reference beingmade to the accompanying drawings, in which

FIG. 1 briefly illustrates a signalling scheme related to embodiments ofthe present disclosure;

FIGS. 2 and 4 illustrate flowcharts of methods according to embodimentsof the present disclosure;

FIG. 3 schematically illustrates queuing management according toembodiments of the present disclosure; and

FIG. 5 illustrates a node according to embodiments of the presentdisclosure.

ABBREVIATIONS

-   -   ACK Acknowledgement    -   AQM Active Queue Management    -   CN Core Network    -   DCCP Datagram Congestion Control Protocol    -   ECN Explicit Congestion Notification    -   FIFO First In First Out    -   IP Internet Protocol    -   LTE Long term Evolution    -   MAC-d Medium Access Control-d    -   OSI Open Systems Interconnection    -   PDU Protocol Data Unit    -   RLC Radio Link Control    -   RNC Radio Network Controller    -   RSVP Resource Reservation Protocol    -   RTCP Real-Time Control Protocol    -   RTP Real-Time Transport Protocol    -   SCTP Stream Control Transmission Protocol    -   SDU Service Data Unit    -   TCP Transmission Control Protocol    -   UDP User Datagram Protocol    -   UE User Equipment    -   UMTS Universal Mobile Telecommunications System    -   WCDMA Wideband Code Division Multiple Access    -   WiMAX World Interoperability for Microwave Access

DETAILED DESCRIPTION

The present disclosure provides a generic method and arrangement forqueue management of IP packets, with which bandwidth greedy services areserved with less probability than services with low requirement onbuffering.

Instead of treating all incoming data for a data flow the same, the dataflow is mapped into sub flows based on the characteristics of the IPpackets. Each sub flow is prioritized differently depending on thetraffic characteristics for the specific sub flow. Applied to bandwidthvarying links in communication networks, real time sensitive serviceswill experience a fairer resource sharing at the sacrifice of bandwidthgreedy services.

Implementing embodiments presented in this disclosure will result inlower delay variance for real time services with lower bandwidthrequirements than available link capacity. This is done on the expenseof services that try to maximize the link utilization.

FIG. 1 presents a simplified signalling scheme of signalling between afirst node 100, a second node 102 and a third node 104. The first node100 sends 106 a flow of Protocol Data Units, PDUs, to the second node102. The second node 102 groups 108 the received PDUs into sub flowsbased on characteristics of the received PDUs. The second node 102determines 108 a priority indicator for each sub flow based on thelength of the sub flows. Having determined a priority indicator, thesecond node 102 selects 110 one or more PDUs in an order of the subflows, which order is indicated by the priority indicator. The secondnode 102 sends 110 the selected one or more PDUs to the third node 104.

FIG. 2 presents a flow chart of method steps for queue management ofPDUs in a node according to the present disclosure. Method step 202comprises receiving a flow of PDUs. In 204 the method associates eachPDU with a flow reference that is determined based on informationelements in at least each PDU header. Step 206 comprises grouping allPDUs having the same flow reference into respective sub flows. In 208the method determines a priority indicator for each sub flow based onthe length of the sub flows. In 210 the method selects one or more PDUsfrom sub flows in an order of the sub flows which is indicated by thepriority indicator. In 212 the method sends the selected PDUs.

FIG. 3 schematically illustrates queuing management according to someembodiments of the present disclosure. At first a flow 302 of PDUs arereceived. These PDUs may be received on a first protocol layer, forinstance layer 3 of the 7-layered Open Systems Interconnection (OSI)model. Based on information elements of the header of at least each PDU,a flow reference is calculated for each PDU. The information elementsmay comprise at least one of the, so called, 5-tuple that is specificfor each session of an application or a service. The 5-tuple comprises aprotocol or application type, a source IP address, a destination IPaddress, a source port and a destination port, which all are at leastassociated with a service session. The flow reference may thus becalculated as a function of the 5-tuple.

A classifier 304 is configured to group the received PDUs into sub flows306 according to the calculated flow reference.

It should be mentioned that all PDUs from one and the same servicesession, has the same information elements, for which reason the flowreference will be the same for all PDUs within an entire servicesession.

Different service sessions may result in the same flow reference, andhence PDUs from different service sessions, may be grouped into the samesub flow. PDUs of instances of different applications may thus well begrouped into the same sub flow. Differently put, one sub flow maycomprise PDU from service sessions of different applications.

PDUs from different service sessions may be grouped into different subflows. The sub flows may thus receive various numbers of PDUs. Differentsub flows may hence comprise a different number of PDUs. Wordeddifferently, the queue length of each sub flow may thus differ from subflow to sub flow.

It should further be mentioned that PDUs within each sub flow may beserved in a FIFO way, i.e. First In First Out. The PDU that was thefirst to be received in the sub flow, will be the first one to beselected from the sub flow. The chronologic order of the PDUs withineach sub flow is thus preserved.

A selector 308 is configured to determine a priority indicator for eachsub flow 306 based on the length of the sub flows. The priorityindicator may be determined based on the number of PDUs in sub flow.

In some embodiments of the present disclosure, the priority indicator isalso based on the PDU length in each sub flow.

Sub flows having only one PDU are assigned with the highest priorityindicator, and thus given the highest priority. One or more PDUs will beselected from sub flows in an order as indicated by the priorityindicator. These selected PDUs will then be sent.

In FIG. 3, an arrow indicates a direction of an example flow 310 that isbeing sent. It should be noted that PDUs may be sent on a protocol layerthat is lower than the one on which PDUs are received.

For instance, if the PDUs are received on protocol layer 3, they may besent on protocol layer 2.

The payload of a PDU of a certain layer N, corresponds to the ServiceData Unit, SDU, of the same layer. Moreover, the PDU of a layer Ncorresponds to the payload or SDU of layer N−1. This means that the PDUsfrom layer 3 will equal to the SDUs of layer 2.

It can be mentioned that the SDU of layer 2 will together with a header,form a PDU of layer 2. In the case of segmentation, a subset of the SDUof layer 2 and a header forms a PDU of layer 2.

The flow 310 may comprise PDUs selected from different sub flows. Thefilling character of each PDU in flow 310, as illustrated in FIG. 3,indicates the sub flow from which the PDUs was selected to be sent. Forinstance, the rightmost PDU of flow 310 was chosen from the bottom mostsub flow of FIG. 3. The second PDU from the right having a firstdiagonal filling, was chosen from the sub flow second from the bottom.The middle PDU in the flow 310 was chosen from the topmost sub flow,whereas the last and second last PDUs were chosen from the second subflow from the top. PDUs of this sub flow have a horizontal fillingcharacter.

It is again stated that the priority indicator of the sub flow is basedon the length of each sub flow. Sub flows having only one single PDUwill be given the highest priority indicator. The rightmost PDU, thesecond PDU from the right and the middle PDU of flow 310, are examplesof PDUs that are chosen from sub flows. Since the sub flows having onlyone single PDU are assigned with the highest priority indicator,selection of PDUs is made from these sub flows having highest priority.

According to some embodiments of the present disclosure, the PDU fromtwo or more sub flows having only one single PDU each is selected on thebasis of the length of the PDU. The shortest PDU may this be chosen,before choosing any of the other single PDUs.

The present disclosure allows a number of different ways to select PDUsas long as they fall within the scope of the present disclosure. Thepriority indicator indicates from which sub flow PDUs are to beselected. The shorter the sub flow is, the higher the priority indicatorof the sub flows. The selecting one or more PDUs from the prioritizedsub flow may be performed in a number of ways.

For instance, the selecting of single PDUs is performed with highestpriority. Selecting of PDUs from sub flows wherein the PDUs are theshortest may also be performed. It is stated that the sub flow having asingle PDU of a certain length, has the highest priority. A sub flowhaving two PDUs, wherein each PDU is less or much less than half thelength of the single PDU, has typically a lower priority indicator.

FIG. 4 presents a flow chart of method steps according to someembodiments of the present disclosure. The method is a method for queuemanagement of PDUs in a node of a radio communication network. Methodstep 402 comprises receiving PDUs of layer N of a Radio Access Bearer(RAB). The RAB is typically established between a core network of theradio communication network and a device with communication capabilitywithin said radio communication network. A RAB comprises one or moreflows of PDUs of service sessions per user. That is, a RAB may forinstance comprise flows of PDUs for a chat session, a surfing session atthe same time as a video call with a friend. The RAB comprises PDUs ofone user or device.

In step 404 the method extracts information from information elements ofthe received layer N PDUs. The information elements may comprise the5-tuple of information, that is the protocol or application type beingused for the service, the source IP address of the PDUs, the destinationIP address of the PDUs, the source port and the destination port, usedby the PDUs.

In step 406 the method determines a flow reference for each PDU based onthe information elements in at least each PDU. The flow reference of onePDU may thus also be based on information elements of another PDU, inaddition to the information elements of said one PDU.

In 408 the method associates the PDUs with the determined flow referenceof each PDU.

In 410 the method groups the received PDUs into sub flows. Herein allPDUs having the same flow reference are grouped in respective sub flows.For instance, all PDUs having the flow reference “10” can be grouped inone sub flow, whereas PDUs having the flow reference “11” are groupedinto another sub flow, since the flow reference “10” is different from“11”.

In 412 the method detects a triggering condition. The triggeringcondition may comprise one of the following: detection of receipt ofMAC-layer information, receipt of information related to the controllayer of Radio Link Control, RLC, and receipt of a PDU into a sub flow.Detection of the triggering condition may trigger step 414 to determinea priority indicator for each sub flow based on the length of each subflow.

The method may further determine the priority indicator for each subflow based on the length of the received PDUs in each sub flow. Also,the determination may comprise to determine the highest priorityindicator to the sub flow having only one single PDU.

In 416 the method selects one or more PDUs from a sub flow in an orderthat is indicated by the priority indicator. In the case a sub flow hasonly one single PDU, this PDU will be selected with highest priorityfrom said sub flow.

In 418 the method encapsulates the selected layer N PDUs to layer N−1PDUs. For instance, in the case a single PDU of protocol layer 3 wasselected in step 416, this PDU is now encapsulated into a PDU layer onlayer 2. The layer 3 PDU here forms the SDU, of the PDU on layer 2.

In step 420 the method sends the selected layer N−1 PDUs. For instance,the selected layer 2 PDU is here sent.

It is added that PDUs that are received may be received on a protocollayer comprising one of: Internet Protocol (IP), Transmission ControlProtocol (TCP), User Datagram Protocol (UDP), Real-Time Control Protocol(RTCP), Datagram Congestion Control Protocol (DCCP), Stream ControlTransmission Protocol (SCTP), Resource reservation Protocol (RSVP),Real-Time Transport Protocol (RTP) and Explicit Congestion Notification(ECN).

In addition, the PDU that are sent may be sent on RLC layer or theMedium Access Control-d, MAC-d, layer.

PDUs of service instances are thus grouped into sub flows. The groupingof these PDUS may be considered to be performed by a sub flowclassification function. Each incoming PDU in the flow 302 is thusgrouped into a sub flow. The PDUs may be considered to be classified andassigned to sub flows. Each sub flow is identified by a unique flowreference. Note that each sub flow has a unique flow reference, whereastwo service sessions may have associated the same flow reference.

It should be emphasized that although grouping and classifying is usedherein, the handling of PDUs should be regarded as logical since the subflows are merely logical sub flows, rather than physical sub flows thatare separated in real space from each other. The handling of the PDUsare however compatible with, and may be understood as, using physicalsub flows.

The properties of the sub flow classification function are such that allPDUs for a service session are assigned to the same sub flow. The PDUsare grouped into sub flows according to the flow reference calculated.When a large number of PDUs have been classified or grouped into subflows, a considerable number of different flow references ranging over alarge flow reference value range, have been calculated.

As mentioned above, the determination of the flow reference is based oninformation elements in the header of the PDUs. The source anddestination addresses and protocol from the PDU headers are used. Whenavailable the source and destination port from layer 4 PDU may also beused.

As noted above, the determined flow reference does not uniquely identifya high layer service, rather a set of services that may share the sameflow reference.

Following the FIFO management, when a maximum number of PDUs has beenbuffered in the sub flow, or when an Active Queue Management (AQM)discard threshold has been reached, the oldest PDU from the longest subflow may be discarded.

PDU handling prior to sending is thus modified to be able to provide aper sub flow priority handling. External restrictions may limit thenumber of sub flows that can be simultaneously active in a system. Forthis reason multiple higher layer data flows may be aggregated into asingle sub flow. Note that a specific higher layer flow of PDUs alwaysis classified to the very same internal sub flow. The number of sub flowto be supported is a trade off between possible resource usage to handleeach sub flow and the maximum number of simultaneous data flows thateach device with communication capability is estimated to have active ona single traffic radio bearer at any point in time.

When a PDU is added to a sub flow, a priority indicator may becalculated, based both on the received PDU length and the sub flowlength, and can be assigned to the PDU.

In order to provide a per sub flow priority handling the PDU handling isthus modified according to the present disclosure.

When for instance a PDU segmentation function requests a new PDU, subflows containing a single PDU is prioritized in the same order as theirpriority indicator indicates. When there are no such flows having asingle PDU, a PDU may be selected from an arbitrary sub flow, for asubsequent segmentation of the PDU before sending the PDUs.

When PDUs from a sub flow has been selected, the PDU may be sent on alower a layer for further processing.

FIG. 5 schematically presents a node 50 for queue management of PDUs.The node 50 comprises a first interface 52 that is configured to receive106, 202, 402 PDUs and associate each PDU with a flow reference that isdetermined based on information elements in at least each PDUs. The node50 also comprises a classifier that is configured to group 108, 206, 410all PDUs having the same flow reference into respective sub flows 306.The node 50 also comprises a selector 56 that is configured to determine108, 208, 414 a priority indicator for each sub flow based on the lengthof the sub flows, and select 110, 210, 416 one or more PDUs from subflows in an order of the sub flows which is indicated by the priorityindicator. In addition, the node 50 comprises a second interface 58 thatis configured to send 112, 212, 420 the selected PDUs.

The selector 56 of the node 50 may further be configured to determinethe priority indicator for each sub flow 306 based on the PDUs groupedinto each sub flow.

The selector 56 of the node 50 may further be configured to determinethe highest priority for each sub flow 306 that has only one single PDU.

The first interface of the node 50 may be configured to associate eachPDU of the same service session with the same flow reference. Each PDUis part of a service session as indicated by the PDU header.

The selector 56 of the node may further be configured to detect 412 atriggering condition that comprises one of detecting receipt ofMAC-layer information, receipt of information related to the controllayer of Radio Link Control, RLC, and receipt of a PDU grouped into asub flow 306. The detecting of the triggering condition may trigger theselector 56 to determine 108, 208, 414 the priority indicator, or toselect 110, 210, 416 one or more PDUs from sub flows. The detecting ofthe triggering condition may trigger the second interface to send 112,212, 420 the selected PDUs.

The first interface 52 of the node 50 may be configured to receive 106,202, 402 PDUs on one protocol layer, whereas the second interface 58 ofthe node 50 may be configured to send 112, 212, 420 the selected PDUs onanother protocol layer, wherein said one protocol layer is a higherprotocol layer than said another protocol layer.

For instance said one protocol layer may be any of: IP, TCP, UDP, RTCP,DCCP, SCTP, RSVP, RTP and ECN.

Said another protocol that may be a lower protocol than the firstprotocol may be RLC layer protocol or MAC-d, layer protocol.

The first interface 52 may also configured to extract information frominformation elements comprising at least one of: a protocol type of theflow, a source IP address, a destination IP address, a source port and adestination port, which all are at least associated with the servicesession.

Moreover, the node 50 may be base station, such as a NodeB, an eNodeB,or a Radio Network Controller (RNC).

According to one example a RNC receives a flow of PDUs from a CoreNetwork (CN) of a communication system.

The present disclosure may be applied to number of link capacitytechniques. Data networks are comprised within the group of networks andaccess techniques within which the present disclosure may beimplemented. In the case of a data network, the node 50 is typically adata server or a network router.

Within WCDMA, the node 50 is a RNC. Looking back at FIG. 1, andimplementing the node 102 as a RNC, node 100 is a Core Network (CN), andnode 104 a NodeB.

When applying the present disclosure to WiMAX, node 102 is implementedas a base station. Applying the present disclosure to LTE, the node 50is preferably implemented as an eNodeB.

Embodiments of the present disclosure come with one or more of thefollowing advantages:

The present disclosure has substantial effect in system where theavailable link capacity varies over time. Especially high effect isgained in systems with transmission links that experience a large delayvariance, for instance mobile communication systems such as UniversalMobile Telecommunications System (UMTS), World Interoperability forMicrowave Access (WiMAX), or Long Term Evolution (LTE).

One advantage with the present disclosure is that it results in reduceddelay variability for real time like services when network transportresources are shared with bandwidth greedy services, such as filetransfers over Transmission Control Protocol (TCP).

Another advantage is a reduced PDU loss probability for real time likeservices when network transport resources are shared with bandwidthgreedy services, such as file transfers over TCP.

Real time services are, in the end to end perspective, sensitive to longdelays, PDU losses, jitter, and insufficient bandwidth. This inventionincreases the chance for real time services to get desired bandwidthcapacity and reduces both the delay variance and the risk for PDUlosses.

It should be emphasized that this disclosure may be varied in many ways.

The elements of an embodiment of this disclosure may be physically,functionally and logically implemented in any suitable way. Indeed, thefunctionality may be implemented in a single unit, in a plurality ofunits or as part of other functional units. As such, this disclosure maybe implemented in a single unit, or may be physically and functionallydistributed between different units, interfaces and processors.

Moreover, even though the embodiments of this disclosure are primarilydescribed in the form of methods and network nodes, they may at leastpartly be embodied in a computer program product, as well as in a systemcomprising a computer processor and a memory coupled to the computerprocessor, wherein the memory is encoded with one or more computerprograms for performing at least a part of the methods described herein.

It is made clear that presented embodiments may well be combined formingnew embodiments not explicitly described herein.

In the claims, the term “comprises/comprising” does not exclude thepresence of other elements or steps. Additionally, although individualfeatures may be included in separate claims, these may be combined, andthe inclusion in different claims does not imply that a combination offeatures is not feasible and/or advantageous. In addition, singularreferences do not exclude a plurality. The terms “a”, “an”, “first”,“second” etc do not preclude a plurality. Reference signs in the claimsare provided merely as a clarifying example and shall not be construedas limiting the scope of the claims in any way.

Although this disclosure has been described above with reference to (a)specific embodiment(s), it is not intended to be limited to the specificform set forth herein. Rather, this disclosure is limited only by theaccompanying claims and, other embodiments than the specific above areequally possible within the scope of these appended claims.

1. A method for queue management of Protocol Data Units, PDUs, in anode, the method comprising; receiving a flow of PDUs, associating eachPDU with a flow reference that is determined based on informationelements in at least each PDU header, grouping all PDUs having the sameflow reference into respective sub flows, determining a priorityindicator for each sub flow based on the length of the sub flows,selecting one or more PDUs from sub flows in an order of the sub flowswhich is indicated by the priority indicator, and sending the selectedPDUs.
 2. The method for queue management of PDUs according to claim 1,wherein the determining of the priority indicator for each sub flow isfurther based on the length of the received PDUs in each sub flow. 3.The method for queue management of PDUs according to claim 1, whereinthe determining of the priority indicator for each sub flow based on thelength of the sub flows comprises determining the highest priority foreach sub flow having only one single PDU.
 4. The method for queuemanagement of PDUs according to claim 1, wherein each PDU is part of aservice session as indicated by each PDU header, and wherein theassociating each PDU with a flow reference comprises associating eachPDU of the same service session with the same flow reference.
 5. Themethod for queue management of PDUs according to claim 1, furthercomprising detecting a triggering condition comprising one of: receiptof MAC-layer information, receipt of information related to the controllayer of Radio Link Control, RLC, and receipt of a PDU into a sub flow,wherein the detecting of the triggering condition triggers thedetermining of the priority indicator, the selecting one or more PDUsfrom sub flows, or the sending of the selected PDUs.
 6. The method forqueue management of PDUs according to claim 1, wherein the informationelements comprises at least one of: a protocol or application type, asource IP address, a destination IP address, a source port, and adestination port, which all are associated with a service session. 7.The method for queue management of PDUs according to claim 1, whereinthe receiving a flow of PDUs comprises receiving a flow of PDUs within asingle Radio Access Bearer, RAB.
 8. The method for queue management ofPDUs according to claim 1, wherein the receiving a flow of PDUscomprises receiving PDUs on a first protocol layer, wherein the sendingthe selected PDUs comprises sending the selected PDUs on a secondprotocol layer, and wherein the first protocol layer is a higherprotocol layer than the second protocol layer.
 9. The method for queuemanagement of PDUs according to claim 8, wherein the first protocollayer comprises any of: Internet Protocol, IP, Transmission ControlProtocol, TCP, User Datagram Protocol, UDP, Real-Time Control Protocol,RTCP, Datagram Congestion Control Protocol, DCCP, Stream ControlTransmission Protocol, SCTP, Resource reservation Protocol, RSVP,Real-Time Transport Protocol, and Explicit Congestion Notification, ECN.10. The method for queue management of PDUs according to claim 8,wherein the second protocol layer comprises RLC layer or Medium AccessControl-d, MAC-d, layer.
 11. A node for queue management of ProtocolData Units, PDUs, the node comprising: a first interface configured toreceive a flow of PDUs and associate each PDU with a flow reference thatis determined based on information elements in at least each PDU header,a classifier configured to group all PDUs having the same flow referenceinto respective sub flows, a selector configured to determine a priorityindicator for each sub flow based on the length of the sub flows, andselect one or more PDUs from sub flows in an order of the sub flowswhich is indicated by the priority indicator, and a second interfaceconfigured to send the selected PDUs.
 12. The node for queue managementof PDUs according to claim 11, wherein the selector further isconfigured to determine the priority indicator for each sub flow basedon the PDUs grouped into each sub flow.
 13. The node for queuemanagement of PDUs according to claim 11, wherein the selector furtheris configured to determine the highest priority for each sub flow havingonly one single PDU.
 14. The node for queue management of PDUs accordingto claim 11, wherein each PDU is part of a service session as indicatedby the PDU header, and wherein the first interface is configured toassociate each PDU of the same service session with the same flowreference.
 15. The node for queue management of PDUs according to claim11, wherein the selector further is configured to detect a triggeringcondition comprising one of: receipt of MAC-layer information, receiptof information related to the control layer of Radio Link Control, RLC,and receipt of a PDU grouped into a sub flow, wherein the detection ofthe triggering condition triggers the selector to determine the priorityindicator, or to select one or more PDUs from sub flows, or the secondinterface to send the selected PDUs.
 16. The node for queue managementof PDUs according to claim 11, wherein the first interface is configuredto receive PDUs on a first protocol layer, and wherein the secondinterface is configured to send the selected PDUs on a second protocollayer, wherein the first protocol layer is a higher protocol layer thanthe second protocol layer.
 17. The node for queue management of PDUsaccording to claim 16, wherein the first protocol layer comprises anyof: Internet Protocol, IP, Transmission Control Protocol, TCP, UserDatagram Protocol, UDP, Real-Time Control Protocol, RTCP, DatagramCongestion Control Protocol, DCCP, Stream Control Transmission Protocol,SCTP, Resource reservation Protocol, RSVP, Real-Time Transport Protocol,RTP and Explicit Congestion Notification, ECN.
 18. The node for queuemanagement of PDUs according to claim 16, wherein the second protocollayer comprises RLC layer or Medium Access Control-d, MAC-d, layer. 19.The node for queue management of PDUs according to claim 11, wherein thenode is a Radio Network Controller, RNC, a Base Station, a NodeB or aneNodeB.